    Patent Document 1: JP 2002-193046 A (corresponding to US2002/0032048)
Patent document 1 describes a technology for an in-vehicle handsfree apparatus to connect a Bluetooth (trade marks, referred to as “BT”) communication link to thereby transmit phone book data registered in a cellular phone.
The BT communication standard includes profiles for a phone book data transfer such as a phone book access profile (PBAP) and an object push profile (OPP). The PBAP is a profile belonging to a so-called pull type of phone book data transfer. In the state where the PBAP is connected, a user only needs an operation to an in-vehicle handsfree apparatus, without need of an operation to the cellular phone, for making the cellular phone transmit all the registered phone book data to the handsfree apparatus. In contrast, the OPP is a profile belonging to a so-called push type of phone book data transfer. In the state where the OPP is connected, a user needs operations to both an in-vehicle handsfree apparatus and a cellular phone for making the cellular phone transmit the registered phone book data to the handsfree apparatus. Further, the user needs to designate a part of phone book data, which should be transmitted from the registered phone book data.
Thus, in view of the user's operability, it looks desirable that the PBAP is first connected between the in-vehicle handsfree apparatus and cellular phone to thereby make the phone book data be transferred from the cellular phone to the handsfree apparatus. Herein, whether the cellular phone is compliant with or has a function of the PBAP can be determined only after the connection procedure is started between the handsfree apparatus and cellular phone. Therefore, in cases that the relevant cellular phone is compliant with the PBAP, the phone book data can be transferred without difficulty as follows. A user performs an operation to instruct the cellular phone to transmit the phone book data. The in-vehicle handsfree apparatus starts a procedure for the PBAP connection to the cellular phone. The in-vehicle handsfree apparatus establishes the connection of the PBAP with the cellular phone. The phone book data registered in the cellular phone is thereby transmitted to the in-vehicle handsfree apparatus.
In contrast, in cases that the relevant cellular phone is not compliant with the PBAP, the phone book data need to be transferred as follows. The in-vehicle handsfree apparatus starts a procedure for the PBAP connection to the cellular phone. The in-vehicle handsfree apparatus fails to establish the connection of the PBAP with the cellular phone. Then, the cellular phone starts a procedure for the OPP connection to the in-vehicle handsfree apparatus. The cellular phone establishes the connection of the OPP with the in-vehicle handsfree apparatus. The user performs an operation to designate a part of phone book data from all the phone book data registered in the cellular phone. The designated phone book data is thereby transmitted to the in-vehicle handsfree apparatus from the cellular phone. That is, the user eventually knows whether the relevant cellular phone is compliant with the PBAP after executing an operation to instruct the cellular phone to transmit the phone book data. In other words, the user needs to know it before the phone book data can be transmitted to the in-vehicle handsfree apparatus from the cellular phone by either the PBAP or OPP. Such procedure reduces the usability.